diff --git a/dhp-workflows/dhp-doiboost/src/main/scala/eu/dnetlib/doiboost/SparkGenerateDoiBoost.scala b/dhp-workflows/dhp-doiboost/src/main/scala/eu/dnetlib/doiboost/SparkGenerateDoiBoost.scala
index 79b9e8183..bc26e44d6 100644
--- a/dhp-workflows/dhp-doiboost/src/main/scala/eu/dnetlib/doiboost/SparkGenerateDoiBoost.scala
+++ b/dhp-workflows/dhp-doiboost/src/main/scala/eu/dnetlib/doiboost/SparkGenerateDoiBoost.scala
@@ -60,7 +60,7 @@ object SparkGenerateDoiBoost {
     val openaireOrganizationPath = parser.get("openaireOrganizationPath")
 
     val crossrefAggregator = new Aggregator[(String, Publication), Publication, Publication] with Serializable {
-      override def zero: Publication = new Publication
+      override def zero: Publication = null
 
       override def reduce(b: Publication, a: (String, Publication)): Publication = {
 
@@ -177,12 +177,43 @@ object SparkGenerateDoiBoost {
       .map(DoiBoostMappingUtil.fixPublication)
       .map(p => (p.getId, p))
       .groupByKey(_._1)
-      .agg(crossrefAggregator.toColumn)
-      .map(p => p._2)
+      .reduceGroups((left, right) =>
+        {
+          //Check left is not  null
+          if (left != null && left._1 != null)
+          {
+              //If right is null then return left
+              if (right == null || right._2 == null)
+                left
+              else {
+                // Here Left and Right are not null
+                // So we have to merge
+                val b1 = left._2
+                val b2 = right._2
+                b1.mergeFrom(b2)
+                b1.mergeOAFDataInfo(b2)
+                val authors = AuthorMerger.mergeAuthor(b1.getAuthor, b2.getAuthor)
+                b1.setAuthor(authors)
+                if (b2.getId != null && b2.getId.nonEmpty)
+                  b1.setId(b2.getId)
+                //Return publication Merged
+                (b1.getId, b1)
+              }
+            }
+          else {
+            // Left is Null so we return right
+            right
+          }
+        }
+
+      )
+      .filter(s => s!= null && s._2!=null)
+      .map(s => s._2)
       .write
       .mode(SaveMode.Overwrite)
       .save(s"$workingDirPath/doiBoostPublicationFiltered")
 
+
     val affiliationPath = parser.get("affiliationPath")
     val paperAffiliationPath = parser.get("paperAffiliationPath")